Plasma is a highly-conductive state of matter resembling an ionized gas. Plasma includes positive ions, which are relatively heavy, and free electrons, which are relatively light and which have become unbound from the positive ions. Although the positive ions remain relatively static, the free electrons move about the plasma freely in response to magnetic and electric fields applied to the plasma. Plasmas are of significant interest at least because, unlike other states of matter, the movement and distribution of plasma particles is dominated by the effects of magnetic and electric fields.